User Guide

Contents

Difference Report

Comparing two results from the command line is a quick way to check for your application regressions. Use the following syntax to create the difference report for the specified analysis results:
vtune
-report <
report_name
> -r <
result1_path
> -r <
result2_path
>
where
  • <
    report_name
    >
    is the type of report for comparison
  • <
    result1_path
    >
    is a directory where your first result file is located
  • <
    result2_path
    >
    is a directory where your second result file is located

Example

This example compares
r001hs
and
r002hs
Hotspots analysis results collected on Linux and displays CPU time difference for each function of the analyzed application. In the result for the optimized application (
r002hs
), a new main function is running for 0.010 seconds, while the Hotspot function algorithm_2 is optimized by 1.678 seconds.
vtune
-report hotspots -r r001hs -r r002hs
Function Module Result 1:CPU Time Result 2:CPU Time Difference:CPU Time algorithm_1 matrix 1.225 1.222 0.003 algorithm_2 matrix 3.280 1.602 1.678 main matrix 0 0.010 -0.010

Generate a Difference Report for Regression Testing

Use the
vtune
command to test your code for regressions on a daily basis:
  1. Create a baseline.
    • Run the
      vtune
      tool to analyze your target using a particular analysis type. For example:
      On Linux*
      vtune
      -collect hotspots -- sample
      On Windows*:
      vtune
      -collect hotspots -- sample.exe
      The command runs a Hotspots analysis on the
      sample
      or
      sample.exe
      target and writes the result to the current working directory. A Summary report is written to
      stdout
      .
    • Generate a report to use as a baseline for further analysis. For example:
      vtune
      -report hotspots -result-dir r001hs
      This creates a Hotspots report that shows the CPU time for each function of the
      sample
      or
      sample.exe
      target.
  2. Update your source code to optimize the target application.
  3. Create and run the script that:
    • On Linux: Sets the path to the
      vtune
      installation folder
    • On Windows: Invokes
      sep-vars.cmd
      in the
      Intel® VTune™
      Profiler
      installation folder to set up the environment.
      The default installation path for the VTune
      Profiler
      varies with the product shipment:
    • Starts the
      vtune
      command to collect performance data.
    • Runs the
      vtune
      command to compare the current result with the initial baseline result and displays the difference. For example:
      vtune
      -R hotspots -r r001hs -r r002hs
      This example compares CPU time for each function in results
      r001hs
      and
      r002hs
      and displays both results side-by-side with the calculated difference. The positive difference between the performance values indicates an improvement for result 2. The negative difference indicates a regression.
      You can compare results of the same analysis type or performance metrics only.
  4. The test is passed if no regressions found.
  5. Repeat steps 2-4 on a regular basis.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804